There was a report in the "Amazon Kindle" forum that the 5.0.4 update damaged a screen rotating hack, which was easily repaired by replacing the .jar file that got overwritten by the update.

Interesting, the .jar files on MY kindle were identical between 5.0.0 and 5.0.4, so amazon must have replaced some potentially user-modified files with original copies.

Yes, I updated to 5.0.4 from 5.0.3 (which was updated from 5.0.1), and now I have the right edge 1-cm chopped off in landscape mode, whereas, that was not a problem in 5.0.3. I don't know all the fancy to get to the jar files, etc. Do you have a simple tar or bin file fix for the right edge chop off in landscape?

The only other difference that I can see from menu surfing in 5.0.4 is an added Legal notice below the Device Info at Menu->Settings->Menu->Legal (maybe it was there before, but I don't remember?).

My only warning about updating to 5.0.4 with YiFan.Lu jailbreaked was that my KT got real flaky getting error popups like

"Unable to Start Application. The selected application could not be started. Please try again. (Close button)".

But after some hard re-booting (I don't exactly remember everything that I did), the KT seems to be stable with 5.0.4, including the jailbreak, screen rotation hack, etc.

Chopped off letters in landscape mode were a problem on 5.0.3 already. See the respective posts therefore, for my KT I can confirm this. Reinstalling the hack solves this, a file from 5.0.1 replaces the actual file. No clue if this has further implications.

I can confirm that jailbreak (with yifanlu's GUI Launcer, landscape mode and custom screensaver hack) works if installed to a KT with 5.0.4.

EDIT: It seems that the letters in landscape mode are indeed chopped off.
EDIT2: KTRotate_0.2 by seaniko7 fixed the letter issue but now pictures in .mobi files won't display correctly (right side of the picture is chopped off).

I can confirm that jailbreak (with yifanlu's GUI Launcer, landscape mode and custom screensaver hack) works if installed to a KT with 5.0.4.

EDIT: It seems that the letters in landscape mode are indeed chopped off.
EDIT2: KTRotate_0.2 by seaniko7 fixed the letter issue but now pictures in .mobi files won't display correctly (right side of the picture is chopped off).

This was already with 5.0.3 the case, either all the text or full pictures.

As I mentioned, I compared 5.0.0 to 5.0.3. Because 5.0.4 INCLUDES all earlier updates, this update did as I described (on MY kindle). But for those who already HAD 5.0.3, you are right, and the only apparent change was then just the kernel upgrade, which apparently only had changes to the inode.c module.

Did anybody look at WHAT changed in inode.c yet? Did they fix a serious bug? Otherwise, what was the urgency of bothering with this update? There are almost no apparent changes since 5.0.0, unless this update UNDID something that was done by 5.0.1 or 5.0.2 or 5.0.3 (which I did not install).